Stop ring for well conduit



M. B. CONRAD STOP RING FOR WELL CONDUIT Nov. 29, 1960 2 Sheets-Sheet 1 Filed May 27, 1957 o: 3 6 a 4 a INVENTOR. A44/@77N bn/,e240

M. B. CONRAD 2,962,313

s'roP RING Foa WELL coNnuIT 2 Sheets-Sheet 2 Nov. 29, 1960 Filed May 27, 1951 Jar/.4.

Anna/V5 STOP RING FOR WELL CONDUIT Martin B. Conrad, Downey, Calif., assignor to Baker Oil Tools, Inc., Los Angeles, Calif., a corporation of California Filed May 27, 1957, Ser. No. 661,843

10 Claims. (Cl. 287-114) The present invention relates to subsurface well equipment, and more particularly to stop rings, and similar devices, adapted to be mounted on well casing, liners, tubing, and similar conduit strings, for the purpose of engaging other apparatus mounted on such strings to move the apparatus with the conduit strings longitudinally through well bores.

An object of the present invention is to provide an improved stop device to be mounted on a conduit string without resort to welding, and the like, for the purpose of contacting and moving a centralizer, wall scratcher, cement basket, and similar apparatus, mounted on the conduit strings through a well bore as the conduit string is lowered therewithin.

l Another object of the invention is to provide a stop device'of the character indicated, which is self-tighten'- ing on the conduit string, and which is capable of safely withstand'ng large longitudinal loads without slipping on the conduit string.

Y A further object of the invention is to provide a stop device of the character indicated, which has a large load transmitting capacity and which can be manufactured at.a very low cost.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may` be embodied. This form is shown in the drawings accompanying and forming part of the present specication. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

s Referring to the drawings:

Figure l is a longitudinal section through a well bore, disclosing a stop device mounted on a casing for coaction with a casing centralizer;

Fig. 2 is a longitudinal section through the stop device;

.- Pig. 3 is an isometric projection of the stop device;

Fig. 4 is an enlarged fragmentary section through the stop device in its initial position on well casing;

Fig. 5 is a view similar to Fig. 4 of the stop device when the casing is moving down'the hole; f

; -Fig. 6 is a View similar to Fig; 4 of the stop device when the casing is moving up the hole.

The specific stop device D disclosed in the -drawings is used for moving a casing centralizer A mounted on the string of well casing B, or other running-in string, through a well bore C with the running-in'string. It is to be'understood, however,`that such devices are also' useful in other relationships, being adapted for engagement with wall scratchers, cementing baskets, and other apparatus mounted on the casing or similar conduit strings,'to be moved longitudinally through the well bore with suchconduit string, aswell as being supported on" the latter.

nited Sites atfv is mounted on a casing section 10 disposed in the well bore C. The centralizer can take any desired form, the one particularly shown including upper and lower longitudinally spaced collars 11, 12 slidable on the casing section 10, which are interconnected by circumferentially spaced, outwardly bowed leaf springs 13, welded or otherwise suitably secured to the upper and lower collars. The springs 13 engage the wall of the well bore C and tend to center the well casing therewithin.

Upper and lower stop rings 14, 15 are secured in longitudinally spaced relation to the upper and lower collars 11, 12, respectively, as by use of circumferentially spaced and longitudinally extending rigid bars 16 attached to both the collars 11, 12 and rings 14, 15 in any suitable manner, as by a welding operation.

The particular centralizer disclosed is of the hinge type, in which the collars 11, 12 and the rings 14, 15 are formed in two parts secured to one another by diametrically opposed hinges 17. The hinges on one side of the device may be disconnected as by removing the hinge pm 19, which then allows the casing centralizer to be swung to open position and placed laterally around the casing section 10, whereupon the centralizer can be closed and the pins 19 reinserted through the hinge knuckles 20, all in a known manner.

The centralizer or casing apparatus A is movable longitudinally through the well bore upon longitudinal movement of the casing B. The stop device D is securedl to the casing section 10, as explained hereinbelow, between the upper and lower stop rings or collars 14, 15,

y such device being engageable with the inner edges 21, 22

I direction with the casing string B within the well bore."

. w,As shown-in the drawings, the casing' Vcentralizer A- Y' of the rings to force the centralizer apparatus through the well bore. For example, the stop device D is engage-- able with the upper edge 22 of the lower stop ring 15 when the casing B is moved downwardly in the well bore to pull the apparatus A and its outwardly bowed springs 13 through the well bore and past any restrictions that might be encountered therein. Conversely, movement of the casing string in an upward direction will cause the stop device D to engage the lower edge 21 of the upper stop ring 14 and pull the centering device A in an upward The particular stop device D disclosed in the drawings is designed to engage the centralizer stop rings 14 and 15, transmitting the force from the casing to such stop rings, the stop device being self tightening so as to lbe more firmly secured to the well casing B as the force transmitted increases. The stop device includes a ring or annular member 30 which is of a substantially greater inside diameter than the outside diameter of the casing section 10 on which the stop device is mounted. This stop ring has inner, upper and lower tapered surfaces 31, 32, the upper surface being inclined in an upward and inward direction, and the lower surface being inclined in a downward and inward direction. Disposed within the ring 30 are one or a plurality of wedge elements 33 initially secured to the central relatively large inside.

diameter portion 34 of the ring. As disclosed, the wedge element or elements 33 are releasably secured to the ring 30, as by means of shear screws 35 extending through` the ring and threaded into the elements. The shear.

screws are preferablyrmade relatively weak. For ex-l be provided, such as by coating the outer surface, of, each wedge 33 with adhesive to secure it to the inner surface of the ring.

"Each wedge 33 has upper and lower `sharp edges 3 6, 37 which project inwardly toward the axis of theV ring' beyond the smallest inner diameter portion of the ring,

which, as illustrated, would be the upper and lower inner edges 38, 39 of the latter. These edges 36, 37 are preferably hard and relatively sharp, so as to be able to dig or bite into the periphery of the Well casing B. As an example, each wedge 33 may be made of mild steel which is then carburized to provide the neces- Sary case hardening.

As disclosed, a plurality of circumferentially spaced Wedges 33 are releasably secured to the ring 30 by means of the relatively weak shear screws 35. These wedges are shown as being about 90 degrees apart, although it is to be understood that the degree of separation between the wedges may be changed to a substantial extent.

Disposed opposite the wedge or wedges 33 is a set screw 40 or a plurality of set screws received within generally threaded radial bores 41 in the ring 30, these screws lying in a central plane of the ring normal to its axis` As disclosed, each set screw 40 is diametrically opposite a wedge 33. Initially, the set screws extend outwardly beyond the outer surface of the ring 30. They may be threaded radially inwardly of the ring 30 by inserting a suitable tool (not shown) in the non-circular socket 42 at the outer end lof each ring, in order to feed the ring radially inward toward a position in which the inner end 43 of each screw will engage the periphery of the well casing B. As each screw is tightened against the well casing, it will pull the ring 30 and the wedges 33 opposite the set screws toward the casing and cause the inner edges 36, 37 of the wedges to dig into the wall of the well casing, in a manner described hereinbelow.

When the set screws d are in their outwardly threaded position, the effective inside diameter of the stop ring device D is greater than the outside diameter of the well casing section on which the stop ring device is to be mounted. Accordingly, the stop ring device D, with the Wedges 33 held in their initial neutral position within the ring 30 by the shear screws 35, can be slipped over an end of the casing 10 and moved to the desired location. The set screws 40 are then threaded inwardly, and as they are tightened against the outer surface of the casing section 10, they will pull the ring 30 transversely of the casing and cause the inner edges 36, 37 of the wedges 33 on the opposite side of the ring 30 to bite or dig into the wall of the casing (Figs. 2 and 4).

The casing centralizer A can then be mounted on the well casing by removing the hinge pins 19 on one side of the centralizer, opening the latter and placing it transversely around the casing with its upper and lower stop rings 14, on opposite sides of the stop ring device D. The centralizer A is then closed and the hinge pins 19 reinserted through the hinge knuckles 20 (Fig. l). The casing sections are then secured to one another and the apparatus lowered in the well bore C.

During downward movement of the casing string B, the lower surface of the ring 30 will engage the lower ring 15 of the casing centralizer, and when the force being transmitted therebetween exceeds the strength of the shear screws 35, the latter are disrupted and the ring 30 is shifted upwardly of the casing B to a slight extent. Such upward shifting of the ring also causes it to move upwardly relative to the wedges 33, since the latter are coupled to the casing by virtue of the sharp edges 36, 37 digging into the latter. Upward movement `of the ring which will be accompanied by a slight upward sliding of the set screws 40 along the surface of the casing, the lower tapered surface 32 of the ring moving along the companion tapered outer surface of the wedge 33 and forcing the inner edges 36, 37 of the latter to ya greater extent into the outer surface of the casing B, more firmly coupling the wedges 33 to the casing and the ring 30 to the casing (Fig. 5). Downward movement can continue and substantial force transmitted through the stop ring 4 device D to the casing centering device A, if need be. The wedges 33 firmly anchor the ring 30 to the well casing B.

If the casing string B is elevated, the stop ring device D will be moved out of contact with the lower collar 15 of the centralizer and into engagement with the upper ring 14 of the centralizer. Such contact of the upper edge of the stop ring 30 with the ring 14 will cause the stop ring 30 to shift downwardly relative to the casing B and the wedges 33, the set screws 40 again sliding down along the casing, with the upper inward tapered surface 31 of the ring then forcing the wedges 33 further into the well casing, the teeth or edges 36, 37 of the latter biting substantially thereinto (Fig. 6).

As the transmitted force increases, the greater is the force wedging or holding the segments 33 against the casing B. Actually, the extent of movement necessary for the wedging action to occur is relatively slight, being of the order of about an eighth of an inch. The ring 30 will be coupled to the casing B very tenaciously, the ring device D being capable of transmitting substantial forces between the casing B and the centering device A when the casing moves longitudinally in the well bore.

Regardless of the direction in which the casing is moved, the upper or lower ends of the ring 30 will engage the companion upper or lower stop rings 14, 15 to appropriately shift the annular member 30 in a relative downward or upward movement with respect to the wedges 33, holding them tirmly anchored against the well casing.

In actual tests of the stop ring device D on popular sizes of well casings, it has been found to withstand total forces of 10,000 to 15,000 pounds, before failure occurred, as by the ring 30 being shifted completely 0E the wedges 33, or the ring 30 being unduly distorted. Such forces are far greater than those normally encountered, so that assurance is had that the stop ring device D will function effectively in transmitting forces between the well casing B, or similar conduit string, and another apparatus mounted thereon, such as the casing centralizer A illustrated in the drawings, by way of example.

Despite the fact that the stop ring device D is capable of transmitting such large forces, its cost of manufacture is rather nominal. One manner of forming the ring 30 is to take a strip of steel, such as mild steel, of the proper length and rolling it into a ring shape, which will then have a cylindrical exterior and interior. The ends of the ring are then welded to one another to form a circumferentially continuous member. The tapered upper and lower inner surfaces 31, 32 of the ring are readily formed merely by imposing an endwise load on the ring to move its upper end toward its lower end, causing its intermediate portion to bulge out, whereby substantially sphericallike inner surfaces 31, 32 are provided, the upper and lower inner edges 38, 39 of the ring being substantially greater than the outside diameter of the casing B on which the ring 30 is to be mounted. The wedges 33 themselves have their outer faces shaped to conform to the inner spherical surface of the member 30, so that there is a surface contact between the ring and the wedges. lOf course, the wedges 33 are appropriately drilled and tapped to receive the shear screws 35, the ring having holes drilled through it for passage of the shear screws 35 into the companion threaded bores of the wedges. The ring 30 is also drilled and tapped for reception of the set screws 40.

While a pair of wedges 33 is provided in the specific example shown in the drawings, and also a pair of set screws 40, it is evident that only a single wedge and a diametrically opposed set screw may be provided, if desired. However, it is preferred to have a plurality of circumferentially spaced wedges 33 and a plurality of opposed circumferentially spaced set screws 40.

It is accordingly apparent Ithat a stop ring device D has been provided which is comparatively inexpensive to assente manufacture and which has a substantial load transmitting capacity. The stop ring device is self-tightening when the load is imposed 'upo'n it, and will not slip or otherwise move on the well casing B when subjected to the loads normally imposed upon it during its operation in the well bore C, in effecting the shifting of its companion apparatus A, mounted on the casing, longitudinally in the well bore.

-The inventor claims:

1. In an annular stop device to be mounted on a running-in string to be lowered in a well bore: an annular member adapted to be disposed on the running-in string and having an inner surface tapering inwardly longitudinally toward the axis of the annular member; a wedge in said member engageable with said inner surface and movable longitudinally with respect thereto; means releasably and initially securing said wedge to said member to prevent such longitudinal movement; and manually operated means on said annular member engageable with the running-in string to shift said annular member and wedge transversely toward the running-in string to engage said wedge with the running-in string prior to release of said releasable means.

2. In a stop device to be mounted on a running-in string to be lowered in a well bore: an annular member adapted to be disposed on the running-in string and having an upper yinner surface tapering upwardly toward the axis of the annular member and a lower inner surface tapering downwardly toward the axis of the annular member; a wedge in said member engageable with said surfaces and movable longitudinally with respect thereto; means releasablsI and initially securing said wedge to said member in a neutral position in engagement with said surfaces; yand manually operated means on said annular member engageable with the running-in string to shift said annular member and wedge transversely toward the running-in string to engage said wedge with the runningin string prior to release of said releasable means.

3. In a stop device to be mounted on a running-in string to be lowered in a well bore: an annular member adapted to be disposed on the running-in string and having an inner surface tapering longitudinally inwardly toward the axis of the annular member; a wedge in said member engageable with said inner surface and movable longitudinally with respect thereto and having longitudinally spaced teeth adapted to bite into the running-in string; means releasabl-y and initially securing said wedge to said member to prevent such longitudinal movement; and manually operated means on said annular member engageable with the running-in string to shift said annular member and wedge transversely toward the running-in string to cause said wedge teeth to bite into the running-in string prior to release of said releasable means.

4. In a stop device to be mounted on a running-in string to be lowered in a well bore: an annular member adapted to be disposed on the running-in string and having an upper inner surface tapering upwardly toward the axis of the annular member and a lower inner surface tapering downwardly toward the axis of the annular member; a wedge `in said member engageable with said surfaces and movable longitudinally with respect thereto and having longitudinally spaced teeth adapted to bite into the running-in string; means releasably and initially securing said wedge to said member in a neutral position in engagement with said surfaces; and manually operated means on said annular member engageable with the running-in string to shift said transverse member and wedge transversely toward the running-in string to cause said teeth to bite into the running-in string prior to release of said releasable means.

5. In an annular stop device to be mounted on a running-in string to be lowered vin a well bore: an annular member adapted to be disposed on the running-in string and having an inner surface tapering longitudinally inwardly toward the axis of the 21111711.1131' member; a wedge in-said. member engageable with saidy innei surface and-- movable longitudinally with respect thereto; and means;

comprising a generally radially arranged screw threaded in said annular member substantially dametrically opning-in string to engage the wedge with the running-in string.

string to be lowered in a well bore: an annular member adapted to be disposed on the running-in string and having an upper inner surface tapering upwardly toward the axis of the annular member and a lower inner surface tapering downwardly toward the axis of the annular member; a wedge in said member engageable with said surfaces and movable longitudinally with respect thereto; and a generally radially arranged screw threaded in said annular member substantially diametrically lopposite said wedge and adapted to be rotated in the annular member into engagement with the running-in string to shift said annular member and wedge transversely toward the running-in string to engage said wedge with the running-in string.

7. In a stop device to be mounted on a running-in string to be lowered in a well bore: an annular member adapted to be disposed on a running-n string and having an inner surface tapering longitudinally inwardly toward the axis of the annular member; a wedge in said member engageable with said inner surface and movable longitudinally with respect thereto and having longitudinally spaced teeth adapted to bite into the running-in string; and means comprising a generally radially arranged screw threaded in said annular member substantially diametrically opposite said wedge and adapted to be rotated in said annular member to be shifted inwardly into engagement with the running-in string to shift said annular member and wedge transversely toward the running-in string to engage said teeth with the running-in string.

8. In a stop device to be mounted on a running-in string to be lowered in a well bore: an annular member adapted to be disposed on the running-in string and having an upper inner surface tapering upwardly toward the axis of the annular member and a lower inner surface tapering downwardly toward the axis of the annular member; a wedge in said member engageable with said surfaces and movable longitudinally with respect thereto and having longitudinally spaced teeth adapted to bite into the running-in string; and means comprising a generally radially arranged screw threaded in said annular member substantially diametrically opposite said wedge and adapted to be rotated in said annular member to be shifted inwardly into engagement with the running-in string to shift said annular member and wedge transverselv toward the running-in string to engage said teeth with the running-in string.

9. In an annular stop device to be mounted on a running-in string to be lowered in a well bore: an annulal member adapted to'be disposed on the running-in suing and having an inner surface tapering longitudinally inwardly toward the axis of the annular member; a wedge in said member engageable with said inner surface and movable longitudinally with respect thereto; shear means releasably securing said wedge to said annular member; and manually operated means on said annular member engageable with the running-in string to shift said annular member and wedge transversely toward the running-in string to engage said wedge with the running-in string.

10. In a stop device to be mounted on a running-in string to be lowered in a well bore: an annular member adapted to be disposed on the running-in string and having an upper inner surface tapering upwardly toward the axis of the annular member and a lower inner surface tapering downwardly toward the axis of the annular member; a wedge in said member engageable with said sur 6. Ina stop device to be mounted von la running-in:

7. faces and movable longitudinally with respect thereto and having longitudinally spaced teeth adapted to bite into the running-in string; shear means releasably securing said wedge to said annular member; and means comprising a generally radially arranged screw threaded in said annular member and adapted to be rotated -in said annular member to be Vshifted inwardly into engagement with the running-in string to shift said annular member and wedge transversely toward the running-in string yto engage said teeth with the running-in string.

References Cited n the tile of this patent UNITED STATES PATENTS De Witt July 20, Gist Apr. 29, Kluck Dec. 23, Kluck Apr. 28, Wright et al Feb. 3, 

